# What is a three phase induction motor and how does it work?

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The working of the three-phase induction motor is based on the principle of electromagnetic induction. When three-phase stator winding of an induction motor is energized from a 3 phase supply, a rotating magnetic field is set up which rotates around the stator at synchronous speed (Ns).

## How does a 3 phase induction motor work?

How it works. To actually achieve torque at the motor shaft, a current is applied across the stator. This creates a rotating magnetic field which in turn induces a current in the rotor. Because of this induced current, the rotor also creates a magnetic field and starts to follow the stator due to magnetic attraction.

## What is 3phase motor?

Three-phase motors are motors designed to run on the three-phase alternating current (AC) power used in many industrial applications. … Three-phase AC has three sources of AC power, all out of phase with each other. That means that no two AC waves are ever at the same point at the same time.

## How does a 3-phase induction motor start?

The three-phase induction motor may be started by connecting the motor directly to the full voltage of the supply. The motor can also be started by applying a reduced voltage to the motor. The torque of the induction motor is proportional to the square of the applied voltage.

## Is a 3-phase induction motor self starting?

Three-phase induction motor is self-starting, because winding displacement is 120 degrees for each phase and supply also has 120 phase shift for 3-phase. It results in a unidirectional rotating magnetic field is developed in air gap which causes 3-phase induction motor to self-start.

## What is working principle of induction motor?

Working Principle of Induction Motor

The motor which works on the principle of electromagnetic induction is known as the induction motor. The electromagnetic induction is the phenomenon in which the electromotive force induces across the electrical conductor when it is placed in a rotating magnetic field.

## What would you use a 3 phase motor for?

Three-phase power is mainly used directly to power large motors and other heavy loads. Small loads often use only a two-wire single-phase circuit, which may be derived from a three-phase system.

## How many volts is a 3 phase?

Electricity is either connected at 230 or 240 volts (single-phase, which accounts for the majority of domestic situations), or 400 and 415 Volts (three-phase). The latter is better suited to providing for powerful appliances and fixed plant, and is more commonly used by industrial and larger commercial users.

## What are the types of 3 phase induction motor?

There are three types of 3- phase induction motors namely plain or squirrel cage induction motor, slip-ring or wound rotor induction motor and double cage rotor induction motor.

## Which type of starter can be used for three-phase induction motor?

Direct-on-line starters are the simplest type of starter. A DOL starter connects an induction motor directly to the power source via a three-phase contactor. A DOL starter usually includes overcurrent protection and overload protection.

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## Can induction motor runs at synchronous speed?

The Induction Motor cannot run at Synchronous speed because the Slip is never zero in an Induction Motor.

## Why is an induction motor called a rotating transformer?

In induction motor, rotor is short circuted, there is no physical contact between stator and rotor. rotor is made to rotate due to induce effect of stator..which is similar to transformer operating principle where primary and secondary magnetically coupled. thats why it is called rotating transformer.

## What happens when induction motor runs at synchronous speed motor will?

So, theoretically, the Induction motor can never run at synchronous speed. … But due to the reduction of speed, again lag influx will be achieved, and the motor will continue to move at this speed due to flux difference between rotor and stator. In short, an induction motor cannot run at induction speed.